UK National Aerospace NDT Board UK NANDTB Near
UK National Aerospace NDT Board © UK NANDTB Near Vision Requirements Presentation complied by UK NANDTB NAndt. B_20 Issue 2 2010 -04 -15 1
UK National Aerospace NDT Board Background © UK NANDTB q EN 4179: 2005 required near vision acuity to Jaeger No. 1 or equivalent, not less than 30 cm/12 in in at least one eye, natural or corrected. q Vision acuity in EN 4179: 2009 changed to 20/25 (Snellen) at 16” (42 cm) +/1” (2. 54 cm) or equivalent in at least one eye, natural or corrected. q There are methods other than Snellen for examining near vision eyesight acuity and there is considerable debate even within the medical field as to “equivalency” of vision requirements. q Responsible Level 3’s will find it difficult to obtain clearly defined supporting medical evidence regarding the equivalency of vision requirements. q The numerous potential avenues for equivalency provides scope for variation and error. NAndt. B_20 Issue 2 2010 -04 -15 2
UK National Aerospace NDT Board Compliance EN 4179/NAS 410 © UK NANDTB 20/25 (Snellen) @ 16” +/- 1” Acceptable Equivalents Jaeger Chart Point Chart #1 @ ≥ 12” N 4 @ ≥ 16” FAA 8500 -1 FAA Potential Others Other ‘Snellen’ Other 16” charts ‘Snellen’ 16” charts BS 4274 -1 (2003) ISO 8596 (2009) Sloan Characters ‘Sans Serif’ font NAndt. B_20 Issue 2 2010 -04 -15 Distance reading standards Not suitable for near vision 3
UK National Aerospace NDT Board Global Standard © UK NANDTB § An agreed global standard for NDT personnel would eliminate the problems of variation and mitigate the risk of error. A standardised solution is required taking the following essential attributes in to consideration: § § § § Optotype size based upon 5 minutes of arc Optotype spacing Eye to optotype distance Illumination Acceptance criteria Use of both eyes (as used for inspection) NAndt. B_20 Issue 2 2010 -04 -15 4
UK National Aerospace NDT Board UK NANDTB Policy © UK NANDTB n Single Option: - Visual acuity tests to be carried out: n Using the UK NANDTB chart and NANDTB/20 n Using the actual eye-wear used in the inspection process – n n n Note: This includes corrective lenses and/or eye protection as normally used. “Equivalents” not permitted within UK jurisdiction Existing certification valid until expiration Responsible Level 3 accountable for training and delegations Note: No Medical/Optical alternative test permitted (eg Optometrist Standard tests) n Functional NEAR VISION Acuity Test n Not for colour vision n Not medical examination – Employers should consider this separately – as for VDU operators etc NAndt. B_20 Issue 2 2010 -04 -15 5
UK National Aerospace NDT Board The Test Chart © UK NANDTB NAndt. B_20 Issue 12 2010 -04 -15 6
UK National Aerospace NDT Board Test Procedure n n n © UK NANDTB OUTLINE: 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) Train/delegate personnel who will administer test Download/Print Chart and verify quality – keep secure Use one block of “E”s - better quality block Verify illumination level Ensure normal eyewear is used Set distance 400± 25 mm Establish the responses to be used Administer test – candidate using both eyes together Start at Line 1 working left to right and moving down lines Acceptance Level is 5 out of 5 up to & including line 9 NAndt. B_20 Issue 2 2010 -04 -15 7
UK National Aerospace NDT Board ADVANTAGES © UK NANDTB § § § Is Universal - No language/alphabet dependency Based on vision acuity – not reading ability Based on resolution of 6 mins of arc - as 20/25 Snellen Can be administered locally Directly controlled by Responsible Level 3 Basically “fail safe” Administered under defined conditions Auditable Based on accepted scientific principles (eg BS 4274 -1, ISO 8596) Can be carried out in inspection area May be carried out in conjunction with annual appraisal NAndt. B_20 Issue 2 2010 -04 -15 8
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